This invention relates to a method and apparatus that illuminates a light guide with a light source mounted to the light guide where the light source is powered through a non-contact coupling that electrically connects the light source to a circuit board.
Instrument clusters for a vehicle are traditionally located on a vehicle dashboard and include several gauges that indicate various vehicle operating conditions. For example, an instrument cluster may include a speedometer, a tachometer, an engine condition indicator, and other known types of gauges. A panel is mounted to a vehicle structure and typically supports graphical images for the gauges indicating the various vehicle operating conditions. A pointer is mounted for movement relative to each graphical image. The pointer is operably coupled to a motor, which selectively moves the pointer relative to the graphical image. The pointer is illuminated by a light source so that the current vehicle operating conditions can be clearly seen by a vehicle operator.
Traditionally, there are two (2) basic types of pointers, a non-active pointer and an active pointer. In the non-active pointer configuration, the pointer is illuminated by a light source that is mounted to a circuit board. The light source can be positioned behind a light transparent output shaft of the motor, or several light sources can be located on the circuit board around the sides of the output shaft. One disadvantage with this configuration is that only a very small portion of the light flux reaches the pointer. Further, the light intensity is not high enough for special instrument panel applications, such as a black panel cluster, for example. It is also difficult to achieve even luminance along the length of the pointer for this light source configuration.
In the active pointer configuration, the light source is secured to the moving pointer. Flexible wires or mechanical contacts are used to make the electrical connection to the circuit board to power the light source. One disadvantage with this configuration is that the mechanical connections are expensive. Further, this configuration requires an intensive manufacturing process, and assembly is difficult. Also, due to the movement of the mechanical connections in response to movement of the pointer, the active pointer system is not always reliable.
In each pointer configuration discussed above, the pointer includes a body portion that extends from a first end coupled to the motor, to a second end that moves relative to the graphical image. The body portion is typically painted along its length in an attempt to provide even illumination along the pointer body. This painting process increases cost and results in additional operational steps that must be performed during production.
Thus, it is desirable to have a method and system that can provide a bright pointer while eliminating operational process steps such as mechanical connections to the light source and painting, as well as overcoming the other above mentioned deficiencies with the prior art.